In many types of structures, in particular buildings having electrical equipment, power stations, transformer stations, and switching stations, it is necessary that a heavy ground conductor pass through a wall of the building. Outside of the building this ground conductor is connected to a heavy-duty ground and inside the building it is connected to the ground of the equipment. Normally such a ground conductor passes through the wall of the building very close to or beneath the ground level.
In most situations the wall is simply formed with the throughgoing hole or one is later broken through it. The ground conductor is passed through this hole, and thereafter the hole is sealed up by means of concrete, special putties, or the like.
Such a procedure has the considerable difficulty that the hole thus made, no matter how carefully it is sealed at the beginning, eventually leaks water. Thus in time water will be able to reenter the building through the hole which is normally adjacent critical electrical equipment.
Furthermore the formation of such a hole and the subsequent sealing of it represents a considerable labor expense and often requires quite some halt in the casting operation during provision of such a ground passing through the wall. Thus the known system is associated with a relatively high labor and installation cost.
Finally the known system has a considerable disadvantage that the ground conductor passing through the wall occasionally contacts the steel reinforcement of the wall. In this manner a so-called false ground is created which can often lie several volts off the real ground. Subsequent determination of real ground potential in a system thus falsely grounded is therefore impossible.